In advanced material processing and precision processing, the conventional processing techniques are no longer sufficient to meet the demands, instead such processes rely heavily on laser microprocessing technique in order to cope with the process demands. In precision processing, visual positioning is one of the means for precision processing.
In general, the control method for a laser processing system with a galvanometer is to employ a reflective mirror to vary an incident angle of a laser light beam, so that the laser light beam is controlled at a pre-processing position of a workpiece. A processing object is capable of forming an image on a charge-coupled device (CCD) in cooperation with coaxial vision technique in order to achieve visual positioning. Since the wavelength ranges of the laser light beam and a visible light beam are different, the optical axis of the laser light beam is caused to be different from the optical axis of the visible light beam, such that optical path error or other potential errors are generated. These errors may cause the image on the charge-coupled device to generate visual errors, thereby reducing the precision of visual positioning.
Thus, visual error of laser coaxial vision module has become one of the concerns for researchers of the related field.